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Author Topic: Power from 2 buildings  (Read 845 times)

Jonathan Johnson

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Re: Power from 2 buildings
« Reply #20 on: September 02, 2014, 12:48:13 am »

Best answer: single generator (or two properly coupled Honda generators) supplying all loads.

Second best answer: balanced audio signal with transformer isolation plus ground lift between devices on separate power sources.

(Edited to clarify that I mean audio signal. The idea of the audio isolation transformer with ground lift is so that there is no direct electrical path between devices that are connected to different power sources, which will prevent hum due to differing ground potential, and may help reduce the possibility of electrical shock or equipment damage in the event of an electrical fault.)
« Last Edit: September 02, 2014, 11:48:03 am by Jonathan Johnson »
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Jeff Bankston

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Re: Power from 2 buildings
« Reply #21 on: September 02, 2014, 01:42:19 am »

Best answer: single generator (or two properly coupled Honda generators) supplying all loads.

Second best answer: balanced signal with transformer isolation plus ground lift between devices on separate power sources.
they might need to hire an electrician especially for the 2nd best answer unless the op is a journeyman electrician with the knowledge on how to configure it.
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Mike Sokol

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Re: Power from 2 buildings
« Reply #22 on: September 02, 2014, 07:27:17 am »

they might need to hire an electrician especially for the 2nd best answer unless the op is a journeyman electrician with the knowledge on how to configure it.

Ref: "Second best answer: balanced signal with transformer isolation plus ground lift between devices on separate power sources."

He's talking about audio isolation transformers, not power isolation transformers, so no electrician required. A good example of a 1:1 audio isolation transformer is the Whirlwind ISO-2, which according to my experiments and discussions with WW will withstand at least 200 volts common mode differential. So it should survive being between an accidentally miswired 120-volt hot-grounded piece of gear connected to a properly grounded one, but in that instance you'll likely have a shock hazard for musicians. 

A good passive DI box with a ground lift should be used between any stage amps and the mixing console at all times. I like the WW IMP2 boxes for a cost effective solution that's tough as nails. Active DI boxes that don't have isolated phantom power supplies won't provide 100% isolation under high-voltage ground differentials, so I tend not to use them. 

Frank DeWitt on this forum builds a beautiful premium passive DI box. Frank... would you mind stepping up to the plate and describing your DI box to the crowd. This is one-time, self-promotional ticket since we're discussing specific DI box usage under adverse conditions.

Keith Broughton

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Re: Power from 2 buildings
« Reply #23 on: September 02, 2014, 08:23:32 am »



He's talking about audio isolation transformers, not power isolation transformers, so no electrician required. A good example of a 1:1 audio isolation transformer is the Whirlwind ISO-2, which according to my experiments and discussions with WW will withstand at least 200 volts common mode differential. So it should survive being between an accidentally miswired 120-volt hot-grounded piece of gear connected to a properly grounded one, but in that instance you'll likely have a shock hazard for musicians. 

A good passive DI box with a ground lift should be used between any stage amps and the mixing console at all times. I like the WW IMP2 boxes for a cost effective solution that's tough as nails. Active DI boxes that don't have isolated phantom power supplies won't provide 100% isolation under high-voltage ground differentials, so I tend not to use them. 

Frank DeWitt on this forum builds a beautiful premium passive DI box. Frank... would you mind stepping up to the plate and describing your DI box to the crowd. This is one-time, self-promotional ticket since we're discussing specific DI box usage under adverse conditions.
With this solution in mind, you could power the PA and FOH from one building and the stage from another. Use iso transformers for any direct connection to the stage gear.
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dick rees

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Re: Power from 2 buildings
« Reply #24 on: September 02, 2014, 11:44:53 am »

With this solution in mind, you could power the PA and FOH from one building and the stage from another. Use iso transformers for any direct connection to the stage gear.

Yup.

But there's still the issue of tripping hazards/traffic and now it's doubled.  It took me a long time to do it, but at this point I walk away from any jobs where the sponsors place such strictures on me.  It's just not worth it.  And when (not if) something goes wrong, even a show stoppage from a tripped and inaccessible breaker, guess who's going to get the blame.

And where do you place your GFCI's?

« Last Edit: September 02, 2014, 12:03:52 pm by dick rees »
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Tim McCulloch

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Re: Power from 2 buildings
« Reply #25 on: September 02, 2014, 12:50:20 pm »

Yup.

But there's still the issue of tripping hazards/traffic and now it's doubled.  It took me a long time to do it, but at this point I walk away from any jobs where the sponsors place such strictures on me.  It's just not worth it.  And when (not if) something goes wrong, even a show stoppage from a tripped and inaccessible breaker, guess who's going to get the blame.

And where do you place your GFCI's?

This, ladies and gentlemen, is the Voice of Experience.  Listen well and heed the advice given.

Ignore any accordion. 8)
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dick rees

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Re: Power from 2 buildings
« Reply #26 on: September 02, 2014, 12:57:26 pm »

This, ladies and gentlemen, is the Voice of Experience.  Listen well and heed the advice given.

Ignore any accordion. 8)

I'd like to dedicate this next number to a long-time fan from Wichita...

Don't forget to tell the sponsors that your cost will include the rental of several hundred feet of yellow jackets...
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Ray Aberle

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Re: Power from 2 buildings
« Reply #27 on: September 02, 2014, 01:27:49 pm »

I'd like to dedicate this next number to a long-time fan from Wichita...

Don't forget to tell the sponsors that your cost will include the rental of several hundred feet of yellow jackets...

I am sure there are plenty available in Corpus Christy, TX.

On the other hand, owning a hundred-hundred fifty feet of Checkers Guard Dogs has been pretty nice the past three years-- not only do I get to use them for my events ("that's ten bucks each for these, thank you very much"), but I can rent them to other companies. Since I splurged and had my logo impressioned on the lid, it's cool renting them to other sound companies, who are advertising my company for me, at their event. :D

Since they rent for so little, that's such a small amount that big events don't even notice the cost. And for a smaller event, if I can give them 60' of ramps for free and it gets me the gig- well, that's a rental item I am OK not always charging for. Makes the customer feel good.

-Ray "who is listening to online streaming radio and wigging out about the trainwrecks" Aberle


...ouch, another one!
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